Sensitized silver halide emulsions



SENSITIZED SILVER HALIDE EMULSIONS Filed July 16, 1957, Ser. No. 672,136

9 Claims. (Cl. 96-107) No Drawing.

This invention relates to photographic silver halide emulsions 'and more particularly to such emulsions containing a non-optical sensitizing agent having at least one polyoxyalkylene group containing at least two oxyalkylene radicals and a small amount of a bisphenol. The invention also relates to photographic elements, e.g., films and papers bearing at least one layer of such an emulsion.

It is known that photographic silver halide emulsions which have been sensitized to very high levels tend to produce fog on development. This photographic fog is due to the existence in the emulsion of silver halide grains which are developable without exposure to light. In addition, fog may be produced in photographic emulsions during-storage, particularly under adverse conditions of temperature and humidity.

As is well known, the sensitivity of photographic emulsions can be increased in a number of ways. One of these is by adding derivatives of alkylene oxides, such as polyoxide with acids, alcohols, or amines such as taught, for instance, by Blake et al. US. 2,400,532; Blake U.S. 2,423,- 549, Blake US 2,441,389 and Carroll et al.: 2,716,062. However, these compounds tend to cause fog when photographic materials, the emulsion of which contain them, are stored for any length of time. Attempts to reduce this fog have involved the use of antifogging agents which are frequently detrimental to certain photographic properties. In particular, such antifoggants tend to reduce the photographic speed of film exposed to relatively low intensity illumination.

It is therefore an object of this invention to provide means for reducing fog in photographic emulsions. Another object is to reduce fog produced on storage of emulsions, particularly in tropical climates or under other adverse conditions of temperature and humidity. A further object of this invention is to provide sliver halide emulsions sensitized with alkylene oxide polymers of improved stability and less tendency to form an objectionable amount of fog on normal storage of photographic elements embodying such emulsions. Still other objects are to achieve the above results without reducing speed or contrast and, in particular, without reducing the speed of the emulsion to low intensity illumination.

The above objects are attained and photographic emulsions and emulsion layers of good stability, speed and contrast which exhibit low fog values upon aging at normal temperatures for extended periods are provided, in accordance with the invention, by admixing (a) fog-inwhere each of R and R is an alkyl radical of 1 to 1 carbon atoms, R and R" are the same or different and are hydrogen, alkyl of l to 18 carbon atoms, cycloalkyl, or aryl, and the hydroxyl groups preferably are in the oor p-position to the radical Q- with (b) a photographic silver halide emulsion containing sensitizing amounts of a non-optical or chemical emulsion sensitizing agent having a molecular weight of at least 282 and containing at least two, and preferably at least six, oxyalkylene units of two to four carbon atoms.

In the aboveformula suitable alkyl radicals include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, pentyl, n-hexyl, n-octyl and t-octyl. Useful aryl radicals include phenyl and naphthyl, and suitable cycloalkyl radicals are cyclopentyl and cyclohexyl.

Many of the bis-type phenols useful in the invention are commercially available and others can be made in like manner by the known prior art procedures including those described in British specification 621,004 and 622,- 977; US. Patent 2,506,486 and those described in J. Am. Chem. Soc. vol. 54, 4325-34 (1932) and vol. 59, 1114 (1937) and Proc. Roy. Soc. vol. 129B, 528-538 (1940).

It has been found that when one or more of the bistype phenols are added to a sensitized emulsion, as described above, in an amount of 4.7 to 30 millimoles per mole of silver halide, that the speed (i.e., the response of the emulsion to radiation of both high and low intensity), contrast and fog values of the resultingemulsions remain substantially at the initial values of the emulsion prior to the addition of the bis-type phenol, even when the emulsions or emulsion layers, are maintained under adverse storage conditions for a short or extended period of time, e.g., atan elevated temperature and/or under cent iodide and the rest bromide.

" be sensitized ,by .means of chemical sensitizing agents other than the polyoxyalkylene polymers mentioned above. Thus, noble metal sensitizers, e.g., gold salts, e.g., chlorauric acid and auric trichloride, may be present in association with sulfur sensitizers, e.g., sodium sulfite, thiosinamine, allylthiourea, sodium thiosulfate,

allyl thiocarbamate, alkali metal thiocyanates and sodium sulfide, these sensitizers to be used in amounts up to 0.005% based on the weight of the silver halide. Moreover, the silver halide emulsions may contain one or more optical sensitizing agents, e.g., cyanine, carbocyanine, merocyanine, pseudocyanine, cyazine etc., dyes.

With regardto the non-optical sensitizers which contain at least one polyoxyalkylene group, there are a relatively large number of such compounds known to the art, suitable compounds being described in the above patents. These compounds include not only the polyalkylene oxides or glycols wherein the oxyalkylene groups contain 2 to 4 carbon atoms but also the condensation products of alkylene oxides of 2 to 4 carbon atoms with glycols, fatty acids, saturated aliphatic amines, and hexitol ring dehydration products, said compounds having a molecular weight of, at least 282, suitable specific compounds of which are disclosed in the aforesaid patents. In general, these sensitizing compounds are present in amounts from 0.1 to 2.0 g. per mole of silver halide.

While gelatin is the preferred binding agent for the silver halide grains, other water-permeable amphoteric' protein protective colloids, e.g., albumin and casein, can be used. Also, agar-agar, alginic acid and the alginates, polyglycuronic acid, polyvinyl alcohol, polyvinyl acetals Fatented Oct. 4, 1960 including those containing color-forming nuclei, and other natural or synthetic water-permeable colloids useful in making photographic emulsions can be used as the original colloid during the precipitation, or in the final emulsion indicated, is 1.6 mole percent iodide and the remainder Y bromide. In these examples the emulsions were prepared and coated in the essential absence of actinic radiation, as is customary in the photographic art.

. Example 1 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds, was divided into three portions. One portion was treated with 0.5 g. of a condensation product of polyethylene oxide with oleyl alcohol (I) having an average molecular weight of approximately 900 (Emulphor ON870-General Aniline & Film Corp.) per mole of silver halide. To a second portion were added 0.5 g. of the condensation product (I) per mole of silver halide together with 5.5 millimoles of 2,2-rnethylen ebis(4-methyl-6-t-butyl-phenol) (II) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control. The emulsions were coated on cellulose acetate film base and were exposed to X-rays in the presence of an intensifying screen at two different intensity levels. The exposure of greater intensity has been designated as No. 2 and that of lower intensity and longer time as No. 1.

The coatings were developed for 5 minutes in a developer of the following composition:

Grams Metol v 3 Anhydrous sodium sulfite Hydroquinone e 9 Anhydrous potassium carbonate 50 Potassium bromide 4.5

Water to make. 1000 ml.

The coatings were tested fresh, after two months of room aging, and after one week at 120 F. and 65% RH. (relative humidity). The aged materials were exposed and developed as described above. Results of tests for speed, gamma and fog, before and after the storage treatment of each of the samples, are given below. Speed is given in terms of a reciprocal of exposure at a density of 0.7. If fog is greater than 0.40 the speed and gamma numbers are of no significance and are therefore not included insuch cases.

FRESH RESULTS No ZExp N 1 po u Compound Amount 7 Fog per Mole Speed Gamma Speed Gamma 820 2. 38 420 2.35 12 i .5 g 9510 p 3.07 4 00 2. 70 40 I-plus II 0.5'g.+5.5 940 2.60 420. 2. 46 18 millif moles Exa pl 2 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds, was divided into three portions. One portion was treated with 0.5 g. of polyethylene oxide (I) having an average molecular weight of from 6000-7500 (Carbowax 6000) (Carbide & CarbonChemicals Company) per mole of silver halide. To a second portion were added 0.5 g. of the polyethyl ene oxide per mole of silver halide together with 30 millimoles of 4,4'-methylenebis(2-t-butyl-6-niethylphenol) (H) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control,

Coating, exposure, and development were carried out s in Exampl 1- FRESH RESULTS 7 No. 2 Exposure No.1 Exposure Compound Amount Fog per Mole Speed Gamma Speed' Gamma Control None 740 2. 29 370 2.11 .26 I .5 g .60 1 plus II 0.5 g.+30 830 2. 70 400 2. 38 .23

millimoles.

ONE MCN'IH RO OM AGING No.2 Exposure, vNo. 1 Exposure Compound v I o Speed Gamma Speed Gamma 640 l 2.10 340 1. 87 .34 1 I plus II; 650 2; 43 360 2.05 .24

ONE WEEK AT F. AND 65% RH.

Fog

ControL. .46 I 2. 30 Iplus II .48

Example 3 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds, was divided into three portions. ,One portion was treated with 0.5 g. of polyethylene oxide (I) having an average molecular weight of from 60004500 (Carbowax 6000) per mole of silver .halide. To a. second portionwere added 0.5. g. of the polyethylene oxide. per mole of, silver halide to: gether with 30 millimoles of 2,2-rnethylenebis(4-t-butyl- 6-methylphenol) (M.P. l37'-139 C.) (II) per mole of silver halide. Neither of these additions were made to a third portion, which was usedas a control.

. No. 2 Exposure No. 1 Exposure Compound Amount Fog per Mole Speed Gamma Speed Gamma Contr None 720 2.37 390 2.09 .26 I- 0.5 Q 58 I plus II 0.5 g.+ 860 2. 79 450 2.69 .22

millimoles 1 MONTH ROOM AGING No. 2 Exposure N o. 1 Exposure Compound Fog Speed Gamma Speed Gamma Control 750 2. 29 410 2. 12 I p1us II 830 2. 78 430 2. 44 :24

ONE WEEK AT 120 E. AND 65% R.H.

Fog

Control 24 T 2.18 I plus II- 24 Example 4 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds, was divided into three portions. One portion was treated with 0.67 g. of Emulphor ON (I) having an average molecular weight of approximately 900 (Emulphor ON870General Aniline & Film Corp.) per mole of silver halide. To a second portion were added 0.67 g. of the Emulphor ON per mole of silver halide together with 20.8 millimoles of 2,2'-methylenebis(4-ethyl-6-t-butylphenol) (II) (Manufactured by the American Cyanamid Company) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control.

Coating, exposure, and development were carried out as in Example 1.

FRESH RESULTS No.2Exposure No.1 Exposure I Compound Amount .Fog'

per Mole Speed Gamma Speed Gamma Control None 880 2.53 410 2.20 .15 .67 1,044 2.91 440 2.37 .26 I plus II 0.67 g.+20 4 960 2. 415 2.11 .17

millimoles.

1 MONTH RooM AGING No. 2'Exposure Compound Fog 7 Speed Gamma Control H 920 2.45 116 I- I 1,108 2.88 .26 Iplus II V 920 2.52 17 7 ONE-WEEKAT 120 ND 65% EH.

Fog

Contr 15 T I .74 IplusII.

Example 5 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds, was divided into three portions. One portion was treated with 0.67 g. of Emulphor ON (I) having an average molecular Weight of approximately 900 (Emulphor ON-870-General Aniline & Film Corp.) per mole of silver halide. To a second portion were added0.67 g. of the Emulphor ON per mole of silver halide together with 10.4 millimoles of 2,2'-methylenebis(3,4dimethyl-6-n-octylphenol) (II) (amorphous solid melting at room temperature) per mole of silver halide. made to' athirdportion, which was used as acontrol.

Coating, exposure, and development were carried out as in Example 1. i

FRESH- RESULTS No. 2 Exposure No. 1 Exposure Compound Amount Fog per Mole Speed Gamma Speed Gamma Control None 132 2. 46 404 2. 09 26 I 0.67 g .56 I plus II 0.67 g.-|10.4 1, 010 2. 456 2.19 .28

millimoles.

1 MONTH ROOM AGING No. 2 Exposure Compound Fog Speed Gamma Control 818 2. 29 r'filiis'ir 1, 036 2. 68 I 30 ONE WEEK AT F. AND 65% R.H.

Fog

Contr .20 I .94 I plus II. 60

Example 6 together with 7.5 millimoles of 2,'2'-n'-butylidenebis(4,6=f

di-t-butylphenol), M.P. 113114 C., (II) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control. 1

. Coating exposure, and development were carried out.

as in Example 1.

. FRESH RESULTS No. 2 Exposure No. 1 Exposure I r Compound Amount Fog per Mole I Speed Gamma Speed Gamma Control None 790 3.04 430 2.53 "29 0.5 g Y .63 I plus II 0.5 g.+7.5 860 2. 62 450 2. 29 19 millimolesx;

1 MONTH ROOM AGING N0. 2 Exposure No. 1 Exposure Compound Fog Speed Gamma Speed Gamma Control 640 2.48 410 I 2.35 Iplus 11; 770 2.30. 390 .219 I16 Neither of these additions were ONE WEEKAT 12519. FJAND 65% R.H.

Example 7 A hishwsp'es s bumi ve ioda a d emul i n. digestedwith sulfur and gold compounds, was divided into three portions. One portion was treated with 0.5 g. of a condensation product of polyethylene oxide with oleyl alcohol (I) having an average molecular weight of appproximately 900 (Emulphor ON870-General Aniline 8: Film Corp.) per mole of silver halide. To a second portion were added 0.5 g. of the condensation product (I) per mole of silver halide together with millimolesof 2,2'-ethylidenebis(4-methyl 6-t octylphenol) (II) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control.

Coating, exposure, and development were carried out as inExample' 1.

The t-octyl radical has the formula C I H; CHa( JC H Hz (2H1 Example 8 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds was divided into three portions. One portion was treated with 0.5 g. of a condensation product of polyethylene oxide with oleyl alcohol (I) having an average molecular weight of approximately 900 (Ernulphof ON870General Aniline & Film Corp.) per mole of silver halide. To asecond portion were added 0.5 g. of the condensation product (I) per mole of silver halide together with 15 millimoles of 4,4:isopropylidenebisphenol manufactured by the Dow Chemical Company (II) per mole of silver halide. Neither of these additions were made to a thirdportion, whichwas used as a control.

Coating, exposure, and development were carried out as in Example 1. I

FRESH RESUI/lS I of silver halide.

5 MONTHS ROOM-AGING g No. 2 Exposure Compound Fog Speed Gamma Control 570 2.11 .36 I- v .44 I plus Ir. 650 2. 29 .18

ONE WEEK AT F. AND 65% RH.

Fog

Qnnrrrn 0 l I 1.10 I plus II .60

Example 9 of 2,2'-n-butylidenebis(6-cyclohexyl-4-ethyl phenol) (II) per mole of silver halide. Neither of these additions were made to a third portiom'which was used as a control.

Coating, exposure, and development were carried out as in Example 1.

FRESH RESULTS No. 2 Exposure No. 1 Exposure Compound Amount Fog per Mole Speed Gamma Speed Gamma Control None 910 2.19 430 2. 23 .32 0.67 E 64 I plus II 0.67 g.+4.7 1,028 2. 59 470 2.20 34 millimoles.

IMONTH ROOM AGING No. 2 Exposure Compound Fog Speed Gamma Contr v 878 2.39 .36 I f .68 I plus II 1,000 2. 50 .34

ONE WEEK AT 120 FJAND 65% RH.

Fog

Control .34 T 1.25 I plus II. 74

Example 10 weight of approximately 900 (Emulphor ON-870'Genoral Aniline & Film Corp.) per mole of silver halide. To a second portion were added 0.67 g. of the Emulphor ON per mole of sil-ver'halide together with 5.2 millimoles of 2,'2'-n-butylidenebis(4-isopropylphenol) II) per mole Neither of these additions were made to a thirdportion, which was used as acontroL as Example 1-.

FRESH RESULTS 1o a and Carbon Chemicals) per mole of silver halide. To a second portion were added 0.5 g. of the polyethylene NoizExposure N04 Exposure oxide per mole of silver halide together with 7.5 milli- Oompound Fog moles of b s(2 n ethyl-4-hydroxy-5-t-butylphenyl)sulfide p Speed Gamma Speed Gamma 5 (II) per mole of silver halide. Neither of these additions were made to a third portlon, which was used as a control. 910 2.19 430 223 I Coating, exposure, and development were carried out .64 1, 000 2. 41 458 2. 59 .28 as m Examp e FRESH RESULTS 1 MONTH .ROOM AGING No.2 Exposure No. 1 Exposure I Compound nrnlollunlt Fog per 0 8 Compound No'zExposure Fog Speed Gamma Speed Gamma Speed Gamma pound (I)\T5OH6 720 2. 37 390 2. 09 Comm, 878 2.39 {36 Iplus II 0.5 830 2. 30 430 2.34 .16

moles. Iplus II 996 2.62 .28

ONE WEEK AT 120 F. and 65% RH. 1 MONTH ROOM AGING F0 No. 2 Exposure N o. 1 Exposure g Compound Fog Comm] '34 Speed Gamma Speed Gamma r 1.25 Iplus Control 750 2.29 410 2.12 .3; I II .13 4 2.12' I14 Example 11 plus 830 2 4 0 A high-speed gelatino-silver iodobromide emulsion, ONE WEEK AT 120 F. AND 05% RH. digested with sulfur and gold compounds was divided 30 into three portions. One portion was treated with 0.67 Fog g. of Emulphor ON (I) having an average molecular weight of approximately 900 (Emulphor ON-870-Gen- 901mm .2; eral Aniline & Film Corp.) per mole of silver halide. Imus H 1% To a second portion were added 0.67 g. of the Emulphor ON per mole of silver halide together with 10.4 millimoles of 2,2'-n-butylidinebis(4-methylphenol) (II) per mole of silver halide. Neither of these additions were made to a third portion, which was used as a control.

Coating, exposure, and development were carried out as in Example 1.

FRESH RESULTS N0. 2 Exposure No. l Exposure Compound Amount 7 Fog per Mole Speed Gamma Speed Gamma Control None 910 2.19' 430 2. 23 1 32 I... 0.071 .64 I plus II 0.67 g. 1,000 2. 91 468 2. 64 .32

10.4 millimoles.

1 MONTH ROOM AGING No.2 Exposure Compound Fog Speed Gamma Control 878 2. 39 36 I- 68 I plus 11..---. 960 3. 10 .36

ONE WEEK AT 120 F. AND 65% RH.

Fog

Contro .34 T .25 I plus IL. 42

Example 12 A high-speed gelatino-silver iodobromide emulsion, digested with sulfur and gold compounds was divided into three portions. One portion was treated with 0.5 g. of polyethylene oxide (I) having an average molecular weight of from 60007500 (Carbowax 6000Carbide In the foregoing examples, the Exposure No. 2 is obtained by using an X-ray tube operated at 71 kvp., 150 milliamps. for A second (i.e., l5 milliamp. seconds). A Dupont Par Speed Intensifying Screen is used together with a 1 mm. aluminum filter, and the samples are exposed at a distance of inches from the tube. The Exposure No. 1 is obtained by using an X-ray tube operated at kvp., 7 'milliamps. for. 9 seconds (i.e., '63 milliamp. seconds). A Dupont Par Speed Intensitying Screen is used. The samples are exposed at a distance of 38 inches from the tube with a /2 mm. aluminum filter in place.

Similar results can be obtained by substituting for the particular bis-type phenols equivalent amounts within the range specified above of p,p-bisphenol, 4,4'-secbutylidenebisphenol, 4,4 n butylidenebis(2 t butyl- 5 methylphenol), 2,2 n butylidenebis(4 ethyl 6- t butylphenol), 4,4 n butylidenebis(2 cyclohexyl- 10 methylene groups between the phenol nuclei wherein the hydroxyl groups are in the orthoand para-positions. These'compounds can be prepared as described in J. Am. Chem. Soc., vol. 62, pp. 413-15 (1940) and J. Chem. Soc. 1942, p. 6849. An important class of compounds is that which contains a chalcogen of atomic number not greater than 16 between two hydroxyphenyl groups which are in the oor p-position to the ether linkage. While it is preferable to use a single phenolic compound in the emulsions, mixtures of any two or even more of any of the above bis-type phenols can be used in the emulsions.

The bis-type phenols used in accordance with the invention are generally added to the emulsions after digestion and after addition of the polyoxyalkylene sensi- 11 sions. Suitable antifogging agents which can be used include benzotriazole nitrobenzimidazole, 1-phenyl-5- mercaptotetrazole, and benzothiazole.

The resulting photographic emulsions can be coated onto any suitable support" to make the desired type of photographic element. Suitable supports include cellulose esters, e.g., cellulose acetate, cellulose nitrate, cellulose acetate butyrate, cellulose propionat e; super polymers, e. g., nylon, polyethylene terephthalate, polyvinyl chloride, poly(vinyl chloride co vinyl acetate) and vinylidene chloride copolymers with vinyl acrylonitrile, etc.; metal sheets or foils, e.g., aluminum and zinc; and paper including resin-coated and barytacoated paper; as well as glass plates, inter alia.

An advantage of this invention is that it provides photographic emulsions and elements with improved stability and aging characteristics. It enables one to obtain the useful sensitizing action of the polyoxyallcylene compounds Without an undue degree of fog being formed upon storage of the photographic elements for long periods.

Another advantage is that the improved emulsions and emulsion layers can be made by the addition of readily available chemical compounds. A further advantage is that the improved emulsions do not require the use of expensive chemicals or tedious procedures. A still further advantageis that the speed of the aforedescribed silver halide emulsions to light of various in tensit ies is not affected to the same degree as known non-phenolic antifogging agents. A closely related advantage is that while the bis-type phenols have an adequate antifogging action in photographic silver halide emulsions sensitized with the polyoxyalkylene compounds referred to above and disclo sed in the citedpatents, they do not have any significant adverse elfect on other photographic properties, e.g., contrast, graininess, resolution, optical sensitization and latent image stability.

acetate,

Hence, once the emulsion is" adjusted to have its opti- 30.0 millimoles of anon-optical sensitizing agent having a molecular weight of at least 282 and containing at least one polyoxyalkylen' group having at least twojoxyalkylene radicals of 2 to 4 carbon atoms area-"tram the group consisting of condensation products of alkylene oxides of 24 carbon atoms with glycols, fatty acids,

saturated aliphatic amines andhexitol ring dehydration products, and (2) from 5+50 millimoles of at least one compound of the general formula wherein Q is a member taken from the group consisting of a direct carbon-to-carbon linkage, O, S--, --(CH where n is 1 to 4, and

where each of R and R is an alkyl radical of 1 to 18 carbonatoms, and R and R" are each a member taken from the class consisting of H, alkyl of 1 to 18 carbon atoms, cycloalkyl and aryl.

2. An emulsion as set forth in claim 1 wherein said sensitizing agent is a polyethylene ether glycol having a molecular weight of at least 1500.

3. An emulsion as set forth in claim 1 wherein said silver halide is silver iodobromide.

4. An emulsion as set forth in claim 1 wherein said colloid is gelatin.

5. A water permeable colloid silver halide emulsion containing per mole o'f silver halide 1) from 4.7 to

30.0 millimoles of a non-optical sensitizing agent having.

saturated aliphatic amines and hexitol ring dehydration products, and (2) from 0.1 to 2 .0 grams of an unsubstituted 0,0alkylidenebisphenol.

6. An emulsion as set forth in claim 5 wherein said colloid is gelatin.

" 7. 'A'water-permeable' colloid silver halide emulsion containing permole' of silver halide (1) from 4.7 to 3 0.0"rr'iillimoles' of a non-tiptical sensitizing agent having a molecular weight of at least 282 and containing at least one polyoxyalkylene group having at least two oxyalkylene radicals of 2 to 4 carbon atoms taken from the group consisting of condensation products of alkyle ne' oxides of 24 carbon atoms with glycols, fatty acids, saturated aliphatic amines and hexitol ring dehydration products, and (2) from 0.1 to 2.0 grams of a bis'phenol of the formula HO Y OH where Y is a chalcogen of atomic number not greater than 16.

8. A photographic element comprising a support bearing at least one layer composed of a photographic emulsion as set forth in claim 1.

9. An element as set forth in claim 8 wherein said support is a hydrophobic ,film base.

References Cited in the file of this patent UNITED STATES PATENTS 2,150,702 Sheppard et 'al. Mar. 14, 1939 2,395,484 Jennings Feb. 26, 1946 2,735,765 Loria et a1. Feb. 21, 1956 2,743,180 I Carroll Apr. 24, 1956 F R N PA E T 1,070,666 if France Feb. 24, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 2355,038- October 4 1%o Thomas David Smith It is hereby certified that error appears in the above numbered pat.- ent requiring correction and that the said Letters Patent should read as corrected below.

Column ll lines 45 and 46, for "4.7 to 30.0 millimols read 0.l to 2.0 grams line 53, for "5-50" read 4.7 to 30.0 column 12 lines 19 and 20, for "4.7 to 30,0 millimoles" read 0, l to 2.0 grams line 27 for "0. l to 2.0 grams" read 4.7 to 3060 millimoles lines 32 and 33 for "497 to 30.0 millimoles" read 0.1 to 2.0 grams line 40, for

"0. l to 2.0 grams" read 4.7 to 30.0 millimoles Signed and sealed this 14th day of November 1961,

(SEAL) Attest: I

ERNEST W. SWIDER DAVID L LADD Attesting Officer Commissioner of Patents USCOM M-DC 

1. A WATER-PERMEABLE COLLOID SILVER HALIDE EMULSION CONTAINING PER MOLE OF SILVER HALIDE (1) FROM 4.7 TO 30.0 MILLIMOLES OF A NON-OPTICAL SENSITIZING AGENT HAVING A MOLECULAR WEIGHT OF AT LEAST 282 AND CONTAINING AT LEAST ONE POLYOXYALKYLENE GROUP HAVING AT LEAST TWO OXYALKYLENE RADICALS OF 2 TO 4 CARBON ATOMS TAKEN FROM THE GROUP CONSISTING OF CONDENSATION PRODUCTS OF ALKYLENE OXIDES OF 2-4 CARBON ATOMS WITH GLYCOLS, FATTY ACIDS, SATURATED ALIPHATIC AMINES AND HEXITOL RING DEHYDRATION PRODUCTS, AND (2) FROM 5-50 MILLIMOLES OF AT LEAST ONE COMPOUND OF THE GENERAL FORMULA 